Effects of Mn²⁺ on the electrical resistance of electrolessly plated Ni-P thin-film and its application as embedded resistor

The effects of manganese sulfate monohydrate (denoted as MSM) on the properties of electroless Ni-P thin-film were investigated. The properties of Ni-P thin-film were examined by means of atomic force microscopy (AFM), cyclic voltammetry, scanning electron microscopy (SEM), X-ray diffraction, energy-dispersive X-ray spectrometer and X-ray photoelectron spectroscopy. AFM and SEM results showed that MSM had significant influences on the morphology, including the formation of smaller nodules, nano-size particles boundaries on both surface and inside of nodules. Due to the specific topologies, the resistance of Ni-P thin-film deposited with MSM was increased. Based on the characterization results, we summarized that the Mn²⁺ or Mn ²⁺-compound were primarily confirmed to act as the stabilizer in Ni-P electroless process. Moreover, the verification test for Ni-P thin-film in application as embedded resistor was carried out through electrical, thermal stability examination by means of current-voltage (I-V), temperature coefficient of resistance and thermal shock tests, respectively. Experiment results demonstrated the Ni-P thin-film deposited with MSM is qualified for embedded resistors.